Silicoborate glass



Patented Apr. 3, 1948 2,439,192

UNITED STATES PATENT OFFICE.

Kuan-Han Sun and Thomas E. Gallear. Rochester, N. Y., assignors to Eastman Kodak Comgany, Rochester, N. Y., a. corporation New ersey No Drawing. ApplicatiouAuzust 9, 1946,. Serial No. 689.531.

1 1 Claim. (01. 1063-54.);

This invention relates to silico-borate glasses including calcium oxide in addition to the five.

' ofrelatively low melting point and of high reoxides already-mentioned:

sistivity against moisture. attack. These glasses because of their clarity, colorlessness, and low TableH' melting point, are particularly useful as base 5: glasses for color filters where the colorant is in- Example 9 m corporated in the glass, particularly those contaming volatile components as the colorant. oxide c w 0 w G Another advantage of the low melting glass is i that it can be conveniently melted in crucibles of 10. 15 *33.2 10 32.0 13 323 15.3 32.0 high silica glass and this eliminates the reaction 2 g 3 g g" of a colorant such as a sulfide or selenide with 20 1310 5 3:1 5 2:9 3:3 2 platinum when the latter is used for the vessel. 18 20 1M 23 39 35.2 40.2 30 In its simplest form the glasses consist of the 39 37 l 42 36 8 oxides of beryllium, aluminum, silicon, boron and of i alkali (hthmm' Sodmm potassmm,) In the following table are given four examples Lithmm 1S perfeljred as.the result-mg glass 15 including zinc, strontium or cadmium oxide in more durable agamst molsture attack addition to the five dominant components.

In Table I are given'seven examples of glass containing only the five oxides mentioned. In bl HI this table the weight and cationic percent of the 6 several oxides are designated W and 0 respectively. Example 12 13 14 -15 TableI Oxide w o w c w o w o ihi 14 .5 32 14.0 32 10 32.7 13.4 32 11100-8 Beo A1014 Sioi gryl l i l l muu 10.3 14 12 145 9.9 14 Exam utium 1s 3 "is W 0 W 0 W 0 W 0 W 0 Cadminm "5' 1 2 21.7 "B 3ogfi1minumm 13% 1g 2 1% 7 1%? 13 0011 17.0 34 11.7 14 3.3 4 20.1 10 44.4 38 19.3 33 10.2 12 3.5 2 20.5 10 47.5 40 3mm 36 39 36 17.7 33 9.9 12 3.4 2 27.7 14 41.3 33 3: 32 3 3: 2 3 3-1 3 1512 32 915 12 10.2 10 1911 10 3919 36 In the following table are given four examples 12 4 14 35 in which barium or lead oxide is added to the five mentioned ingredients: L i m i t a Weight percent-.- 8-18 3-10 25-23 10-34 21-45 L 1 m 1 t 8 Example 10 17 18 19 Cationic per cent-.- 27-33 3-18 2-10 10-13 30-40 40 Oxide wowowowo Lithium 10.7 29.9 3.4 27.8 15 33.7 10.7 30 It is to be understood that other oxides maybe Eggg 1-3 3-1 3% 11 added or substituted in part, but in any event the Tfind '15 2.3 32.0 five oxides mentioned total over fifty percent, and 3 3 $2 3:2 2 3:: 3:1 3 Preferably over ei hty pe y Weight, and BoronLII 27.9 33.5 21.9 31.3 39 37.5 30.9 37 over eighty cationic percent and preferably over ninety cationic percent.

In the following table are given four examples 0 The following and last example includes small amounts of a large number of oxides in addition to the five principal ones:

The glassses having a high beryllium content are more durable than thosewith equivalent amounts of aluminum. Glasses having high barium content are relatively less durable than others.

a i A It is understood that, as is usual in glass-making, the ingredients may be introduced in compounds other than the oxides, to which they are transformed in the furnace.

Since L110, A1203, etc. are empirical formulas, it is equally expedient and more convenient, particularly in using cationic percentages, to adopt the form 301.5, LaO1.s, etc.

A glass resulting from a batch containing: lithium oxide, 8 to 18 percent or 27 to 38 cationic percent; beryllium oxide, 3 to 16 weight percent 'or 3 to 18 cationic percent; aluminum oxide, 2.5

to 23 weight percent or 2 to cationic percent; silicon oxide, 10 to 34 weight percent or 10 to 18 cationic percent; boron oxide, 21 to 45 weight I percent or 3il to 40 cationic ercent.

In making the glasses herein describedithe batch materials are thoroughly mixed in dry powdered form and fed into a platinum vessel inside a furnace. Those containing lead oxide as a component are more conveniently melted in a vessel of high silica glass. The batch melts to a clear liquid at about 1050 C. or below, the

. length of time depending on the amount and composition of the batch and may be from a quarter hour to several hours. The liquid is usually fairly fluid and may be shaken or stirred to uniformity. It is then poured into a mold previously heated to about 350-550 C. and cooled down slowly to room temperature, All the glasses are colorless. V

KUAN-HAN SUN. THOMAS E. CALLEAR.

mmms CITED flheifollowing references are of record in the file of this patent:

UNITED STATES PATENTS V Number V Name 1 Date 1369 321 Hood June 26, 1934 FOREIGN PATENTS Number Country Date 7 477,698 Great Britain 1933 Having described our invention, what we claim 

